Understanding Run‑Flat and Extended Mobility Tyres
If you’re replacing tyres on a premium vehicle, you may come across terms like Run‑Flat Tyres or Extended Mobility Tyres (EMT). These technologies were developed to solve the same challenge: helping you keep moving safely after a puncture or sudden loss of air pressure.
While they share a similar purpose, they’re built differently and your vehicle may require one specific type.
What are Run‑Flat Tyres?
Run‑Flat Tyres are engineered to help you continue driving for a limited distance after a puncture, giving you time to reach a safe location or a tyre professional.
They use a reinforced sidewall construction designed to support the vehicle even with little or no air pressure. This technology is fitted to many performance and luxury vehicles, where maintaining control after a puncture is essential.
For a deeper dive into how Run‑Flat Technology works, read our article: Run Flat Tyres: Keep on Going.
What are Extended Mobility Tyres (EMT)?
Extended Mobility Tyres were developed with the same goal as Run‑Flat Tyres — temporary mobility after a loss of pressure — but with a focus on improved ride comfort.
EMTs use a similar self‑supporting sidewall design, but with reduced sidewall thickness compared with traditional Run‑Flat Tyres. This helps deliver a smoother ride during everyday driving while still providing short‑distance mobility after a puncture.
A key detail: Some EMT tyres may still display “RFT” on the sidewall. This is normal and reflects trademarked naming rather than construction. The true tyre type is determined by the OE (Original Equipment) specification and ISO sidewall symbol.
Which vehicles use these technologies?
Vehicle manufacturers choose the tyre technology that best suits the engineering and safety requirements of each model.
Extended Mobility Tyres (EMT / MOE / RE0) Commonly fitted as original equipment on more recent versions of selected:
- Audi models (RE0)
- Mercedes‑Benz models (MOE or MOExtended specification)
- Lexus LS and NX models
Traditional Bridgestone Run‑Flat Tyres (RFT) Commonly fitted as original equipment on selected:
- Alfa Romeo
- BMW
- Ferrari
- Lamborghini
- Mazda (MX‑5 ~2005)
- Nissan (GT‑R)
Because OE specifications vary between models and years, it’s important to fit the correct replacement tyre. Your local Bridgestone Select Tyre & Auto store can help identify the right tyre for your vehicle.
Why does the correct tyre type matter?
Although Run‑Flat and Extended Mobility Tyres both provide temporary mobility after a puncture, they are different technologies and are not always interchangeable.
Your vehicle manufacturer specifies the tyre technology best suited to your vehicle, so it's important to replace your tyres with the correct original equipment specification. Fitting the wrong type can affect performance, comfort, and safety.
Run-flat tyres require a special, less-common wheel rim design that helps prevent the tyre from leaving the wheel when it is running without air. Extended Mobility tyres use more commonly available wheel rims.
Both technologies also require a Tyre Pressure Monitoring System (TPMS) to alert you if pressure is lost. This is because it may not be immediately obvious that a run-flat or extended mobility tyre is running without air, and after some time in this condition the tyre can fail in a more significant and sudden way.
Need help choosing the right tyre?
If your vehicle is fitted with Run‑Flat or Extended Mobility Tyres and you’re unsure which replacement tyre is correct, visit your local Bridgestone Select Tyre & Auto store. Our experts can identify the right OE specification and help keep you driving with confidence.
Frequently Asked Questions
Can I continue driving after a puncture?
Yes — both Run-Flat and Extended Mobility Tyres are designed to provide temporary mobility after a puncture. They are not intended for long-term use once pressure is lost.
Are run-flat and extended mobility tyres able to be repaired?
While more recent run-flat tyres are generally repairable, the longer you drive without air, the more likely the tyre will be permanently damaged and unable to be repaired.
How do I know which technology my vehicle uses?
Many premium vehicles specify one of these technologies as original equipment. If you’re unsure, your local Bridgestone Select Tyre & Auto store can confirm the correct OE specification.
Can I replace an EMT tyre with a Run-Flat Tyre?
No — always replace tyres with the OE specification recommended for your vehicle. If you’re considering a change, speak with a Bridgestone tyre professional first.
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